• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.234-234
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• 2010

The PR transitions in asymmetric dot-in-double-quantum-well (DdWELL) photodetector is identified by bias-dependent spectral behaviors. Discrete n-i-n infrared photodetectors were fabricated on a 30-period asymmetric InAs-QD/[InGaAs/GaAs]/AlGaAs DdWELL wafer that was prepared by MBE technique. A 2.0-monolayer (ML) InAs QD ensemble was embedded in upper combined well of InGaAs/GaAs and each stack is separated by a 50-nm AlGaAs barrier. Each pixel has circular aperture of 300 um in diameter, and the mesa cell ($410{\times}410\;{\mu}m^2$) was defined by shallow etching. PR measurements were performed in the spectral range of $3{\sim}13\;{\mu}m$ (~ 100-400 meV) by using a Fourier-transform infrared (FTIR) spectrometer and a low-noise preamplifier. The asymmetric photodetector exhibits unique transition behaviors that near-/far-infrared (NIR/FIR) photoresponse (PR) bands are blue/red shifted by the electric field, contrasted to mid-infrared (MIR) with no dependence. In addition, the MIR-FIR dual-band spectra change into single-band feature by the polarity. A four-level energy band model is proposed for the transition scheme, and the field dependence of FIR bands numerically calculated by a simplified DdWELL structure is in good agreement with that of the PR spectra. The wavelength shift by the field strength and the spectral change by the polarity are discussed on the basis of four-level transition.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.11 no.1
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• pp.65-73
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• 2005

Osteoarthritis has been considered a disease of the elderly because it is uncommon before the age of 40 years and is seen in approximately 80% of United States citizens older than 65 years. general population on kuri city in korea revealed that prevalence of knee osteoarthritis is 10.2%, increasing with age. High level of physical activity in men and age, post-menopause and obesity in women can be risk factor. Osteoarthritis is no evidence that a acquired process initiated much earlier in life through mechanical, metabolic, genetic, or other origins. A high tibial osteotomy alters static lower extremity alignment thereby decreasing medial compartment loading. As well, conservative treatment strategies, such as knee braces and valgus heel wedges, affect lover limb mechanics and attempt to reduce medial compartment loading. It was hypothesized that valgus heel wedges and modified orthoses would shift the center of pressure laterally on the foot during level walking, reducing the moment arm of the adduction moment in the frontal plane, thereby resulting in a decrease in the knee adduction moment. In the 1980s, the effect of wearing a laterally wedged insole on osteoarthritic patients with a varus deformity of the knee was firsted, and since then, kinematic and kinetic analyses concerning this condition have mainly focused on a static standing position. Since the early 1990s, the beneficial effect of wearing a laterally wedged insole to treat osteoarthritis of the knee has also been reported in dynamic conditions, but these studies did not answer the question of the kinematic and kinetic mechanisms that resulted in the reduced symptoms in patents with knee osteoarthritis. therefore, the effect of wearing laterally wedged insole has not been sufficiently studied.

• International Journal of Railway
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• v.6 no.2
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• pp.33-44
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• 2013

In recent years, energy consumption in the transportation sector by expanding motorization continues to increase in almost every country in the world. Moreover, the growth rate of the transportation energy consumption is significantly higher than those of the civilian and industrial sectors. Therefore, every country strives to reduce its dependence on private transport, which is the main contributor to the transportation energy consumption. In many countries, concepts such as Transit Oriented Development (TOD) or New Urbanism, which controls road traffic by increasing the proportion of the public transportation significantly, have been implemented to encourage a modal shift to public transport. However, the level of change required for eliminating environmental problems is a challenging task. Minimizing transportation energy consumption by controlling the increase of the traffic demand and maintaining the level of urban mobility simultaneously is a pressing dilemma for each city. Grasping the impact of the diversity of the urban transport and infrastructure is very important to improve transportation energy efficiency. However, the potential for reducing urban transportation energy consumption has often been ineffectively demonstrated by the diversity of cities. Therefore, the accuracy of evaluating the current efficiency rate of the urban energy consumption is necessary. Nevertheless, quantitative analyses related to the efficiency of transportation energy consumption are scarce, and the research on the current condition of consumption efficiency based on international quantitative analysis is almost nonexistent. On the basis of this background problem definitions, this research first built a database of the transportation energy consumption of private modes in 119 cities, with an attempt to reflect individual travel behaviors calculated by Person Trip data. Subsequently, Data Envelopment Analysis (DEA) was used as an assessment method to evaluate the efficiency of transportation energy consumption by considering the diversity of the urban traffic features in the world cities. Finally, we clarified the current condition of consumption efficiency by attempting to propose a target values for improving transportation energy consumption.

• Korean Journal of Occupational Health Nursing
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• v.8 no.2
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• pp.162-168
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• 1999

To investigate industrial fatigue and low back pain, the questionaire survey for subjective symptoms of fatigue and low back pain was carried out 305 nurses in general hospital in Korea. Nurses participated to this study were divided into low back pain group(LBP) and control group, according to the self-reports by written questionaires. The subjective sysptoms of fatigue comprised three groups of 10 items each, representing dullness and sleepiness(level of cerebral activation), difficulty in concentration(level of motivation) and bodily projection of fatigue. The resultant data were processed for $x^2$-test, t-test to confirm the associations. The results were as follows: 1. 28 items of fatigue subjective symptoms exept two item, 'feel thirsty and 'feel ill', were directly associated with low back pain. 2. The percentage of fatigue complaint were significantly higher in LBP group than control. 3. Of the 30 items of fatigue subjective symptoms, the highest percentage was accounted for 'legs feel heavy', 'eye strain', 'feel stiffness in the neck or the shoulders' followed by 'feel like lying', 'whole body feels tired', 'feel a pain in the low back', 'feel drowsy' and in the order of sequence. 4. The average weighted score for the first group of fatigue items(dullness and sleepiness) was the largest among three groups and was followed by the second group(difficulty in concentration) and the third group (bodily projection of fatigue) in the order of sequence, suggesting the heavier mental and shift work stress of the female workers.

• Journal of the Korea Convergence Society
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• v.8 no.9
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• pp.9-16
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• 2017

In this paper, sub-microwave oscillator sensor is proposed to non-invasively monitor the glucose concentration level of the human biological tissue by oscillation frequency variation. Inductive slot in the ground plane of the microstrip line is combined with the biological tissue, to realize the resonator as a part of the oscillator sensor. The phantom box mimicking the human tissue is introduced for simulation of the resonator which resonance frequency correspondingly shifts up on three step glucose concentration levels(0, 400, 800 mg/dL). Oscillator sensor circuit is fabricated as a prototype. Pig tissues instead of human is used. Oscillation frequency shift of about 14 MHz per glucose level of 400 mg/dL has been successfully measured around 1,100 MHz. This proves that the proposed sensor is applicable to a blood glucose sensor.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.5
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• pp.201-205
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• 2003

We synthesized dendrimers containing light switchable units, azobenzene group. And the dendrimer containing 48 pyridinepropanol functional end group, which could form a complex structure with metal ions was synthesized. To apply to the molecular level devices or data storage system using Langmuir-Blodgett(LB) film, we firstly investigated the monolayer behavior using the surface pressure-area($\pi$-A) isotherms at air-water interface. And then the surface pressure shift of monolayer by light irradiation was also measured to the dendrimer with azobezene group. As a result, the monolayer of dendrimer with azobenzene group showed the reversible photo-switching behavior by the isomerization of azobenzene group in their periphery. The samples for electrical measurement were fabricated to two types which were pure dendrimer with pyridinepropanol group and its complexes with $Pt^4+$ ions by LB method. We have studied the electrical properties of the ultra thin dendrimer LB films investigated by the current-voltage(I-V) characteristics of Metal/Dendrimer LB films/Metal(MIM) structure. And we have investigated different results in the surface activity at the air-water interface as well as the electrical properties for the monolayers of pure dendrimer with pyridinevopanol group and its complex with $Pt^4+$ ions. In conclusion, it is demonstrated that the metal ion around dendrimer with pyri야nepropanol group can contribute to make formation of network structure among dendrimers and it result from the change of electrical properties. This results suggest that the dendrimers with azobenzene group and pvridinedropanol group can be applied to high efficient nano-device of molecular level.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.5
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• pp.201-201
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• 2003

We synthesized dendrimers containing light switchable units, azobenzene group. And the dendrimer containing 48 pyridinepropanol functional end group, which could form a complex structure with metal ions was synthesized. To apply to the molecular level devices or data storage system using Langmuir-Blodgett(LB) film, we firstly investigated the monolayer behavior using the surface pressure-area($\pi$-A) isotherms at air-water interface. And then the surface pressure shift of monolayer by light irradiation was also measured to the dendrimer with azobezene group. As a result, the monolayer of dendrimer with azobenzene group showed the reversible photo-switching behavior by the isomerization of azobenzene group in their periphery. The samples for electrical measurement were fabricated to two types which were pure dendrimer with pyridinepropanol group and its complexes with $Pt^4+$ ions by LB method. We have studied the electrical properties of the ultra thin dendrimer LB films investigated by the current-voltage(I-V) characteristics of Metal/Dendrimer LB films/Metal(MIM) structure. And we have investigated different results in the surface activity at the air-water interface as well as the electrical properties for the monolayers of pure dendrimer with pyridinevopanol group and its complex with $Pt^4+$ ions. In conclusion, it is demonstrated that the metal ion around dendrimer with pyri야nepropanol group can contribute to make formation of network structure among dendrimers and it result from the change of electrical properties. This results suggest that the dendrimers with azobenzene group and pvridinedropanol group can be applied to high efficient nano-device of molecular level.

• Korean Journal of Applied Biomechanics
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• v.28 no.1
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• pp.9-18
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• 2018

Objective: This study aimed to analyze how the upright body type exercise program affected body balance and record of archers. This study aimed to prove the effectiveness of upright body type exercise, on this basis, in enhancing the performance of archery players. Method: A total of 14 archers (7 men and 7 women) in B Metropolitan City who had ${\geq}4years$ of career in archery and were given explanation of its contents and purpose before giving spontaneous consent to the experiment were enrolled in the study. The upright body type exercise program was implemented thrice a week for 12 weeks, with higher exercise intensity with time. A resistive pressure sensor, Gaitview AFA-50, was used to measure the foot plantar pressure distribution and analyze quantitative information concerning variation in posture stability and weight shift in dynamic balance of foot plantar pressure in shooting and static balance of plantar pressure with the eyes open and closed and the change in archery record accompanying the change in body balance. Results: As for the differences in foot plantar pressure between before and after participation in the upright body type exercise program, there was no significant difference in static balance of foot plantar pressure with the eyes open, and there was statistically significant difference at the ${\alpha}=.05$ significance level in static balance of foot plantar pressure with the eyes closed or in dynamic balance of foot plantar pressure in shooting. There was statistically significant difference at the ${\alpha}=.05$ significance level in archery record. Conclusion: The upright body type exercise program had positive effects on static and dynamic balance of foot plantar pressure by allowing archers to experience less body sway and physical imbalance in shooting with closed eyes and positive effects on archery record. Thus, the program is expected to help archers correct their posture and perform better.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.1
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• pp.23-37
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• 2017

Objectives : This study was conducted to evaluate the level of exposure to volatile organic compounds (VOCs) among workers handling rust preventive oils. Methods : A total of 30 bulk samples and 54 personal air samples were collected using diffusive samplers at 22 workplaces handling rust preventive oils in Daegu and Gyongsangbuk-do Province from March to October 2013. We also investigated detailed information on the related work conditions, such as kinds of products, handling methods, local exhaustive ventilation systems, and the status of the wearing personal protective equipment. All bulk samples and air samples were analyzed using gas chromatography mass spectrometry (GC-MS) to identify components to which workers potentially were exposed. Quantitative airborne concentrations of VOCs were confirmed using gas chromatography with flame ionized detectors. Results : In terms of qualitative analyses for the 30 bulk samples, we found carcinogenic, mutagenic and reproductive toxic(CMR) substances such as butane(carcinogenic Group 1A, mutagenic Group 1B), butoxy ethanol(carcinogenic Group 2), cumene (carcinogenic Group 2), ethyl benzene(carcinogenic Group 2), methyl isobutyl ketone(carcinogenic Group 2) and toluene (reproductive toxic, Group 2). As a result of full-shift based personal air samples, eight substances such as n-hexane, n-heptane, octane, nonane, decane, toluene, ethyl benzene and xylene were detected. Among them, n-hexane and n-heptane were detected in all of 54 air samples with $13.13mg/m^3$ and $8.61mg/m^3$ of maximum concentration, respectively. The level of airborne concentration from all of samples were bellow the occupational exposure limit in Korea. Conclusions : Based on the results of this study, workers handling rust preventive oils could be exposed to CMR substances contained in rust preventive oils and n-hexane and n-heptane were found as the most frequent sources of VOC exposure.

• Archives of Pharmacal Research
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• v.29 no.7
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• pp.570-576
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• 2006

Phytoestrogen biochanin A is an isoflavone derivative isolated from red clover Trifolium pratense with anticarcinogenic properties. This study examined the action of biochanin A with the carcinogen activation pathway that is mediated by the aryl hydrocarbon receptor (AhR) in MCF-7 breast carcinoma cells. Treating the cells with biochanin A alone caused the accumulation of CYP1A1 mRNA and an increase in CYP1A1-specific 7-ethoxyresorufin O-deethylase (EROD) activity in a dose dependent manner. A concomitant treatment with 7,12-dimethylbenz[a]anthracene (DMBA) and biochanin A markedly reduced the DMBA-inducible EROD activity and CYP1A1 mRNA level. In addition, the biochanin A treatment alone activated the DNA-binding capacity of the AhR for the dioxin-response element (DRE) of CYP1A1, as measured by the electrophoretic-mobility shift assay (EMSA). EMSA revealed that biochanin A reduced the level of the DMBA-inducible AhR-DRE binding complex. Furthermore, biochanin A competed with the prototypical AhR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), for binding to the AhR in an isolated rat cytosol. The biochanin A competitively inhibited the metabolic activation of DMBA, as measured by the formation of the DMBA-DNA adducts. These results suggest that biochanin A may thus be a natural ligand to bind on AhR. Therefore, biochanin A may be due to act an antagonist/agonist of the AhR pathway.